System and method for the synchronization of a file in a cache

ABSTRACT

The invention provides a system and method for file synchronization. One embodiment of the system of this invention includes a software program stored on a computer readable medium. The software program can be executed by a computer processor to receive a file from a server; store the file as a cached file in a cache; determine if the cached file has been modified; and if the cached file has been modified, communicate the cached file directly to the database.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims a benefit of priorityunder 35 U.S.C. §120 to U.S. patent application Ser. No. 15/017,189,filed Feb. 5, 2016, entitled: “SYSTEM AND METHOD FOR THE SYNCHRONIZATIONOF A FILE IN A CACHE,” which is a continuation of and claims priority toU.S. patent application Ser. No. 14/797,758, filed Jul. 13, 2015,entitled: “SYSTEM AND METHOD FOR THE SYNCHRONIZATION OF A FILE IN ACACHE,” issued as U.S. Pat. No. 9,292,536 on Mar. 22, 2016, which is acontinuation of and claims priority to U.S. patent application Ser. No.14/107,906, filed Dec. 16, 2013, entitled: “SYSTEM AND METHOD FOR THESYNCHRONIZATION OF A FILE IN A CACHE,” issued as U.S. Pat. No. 9,110,911on Aug. 18, 2015, which is a continuation of and claims priority to U.S.patent application Ser. No. 13/875,913, filed May 2, 2013, entitled:“SYSTEM AND METHOD FOR THE SYNCHRONIZATION OF A FILE IN A CACHE,” issuedas U.S. Pat. No. 8,645,318 on Feb. 4, 2014, which is a continuation ofand claims priority to U.S. patent application Ser. No. 13/335,782,filed Dec. 22, 2011, entitled “SYSTEM AND METHOD FOR THE SYNCHRONIZATIONOF A FILE IN A CACHE,” issued as U.S. Pat. No. 8,452,728 on May 28,2013, which is a continuation of and claims priority to U.S. patentapplication Ser. No. 12/545,423, filed Aug. 21, 2009, entitled “SYSTEMAND METHOD FOR THE SYNCHRONIZATION OF A FILE IN A CACHE,” issued as U.S.Pat. No. 8,117,152 on Feb. 14, 2012, which is a continuation of andclaims priority to U.S. patent application Ser. No. 11/328,526, filedJan. 10, 2006, entitled “SYSTEM AND METHOD FOR THE SYNCHRONIZATION OF AFILE IN A CACHE,” issued as U.S. Pat. No. 7,590,665 on Sep. 15, 2009,which in turn is a divisional of and claims priority to U.S. patentapplication Ser. No. 10/033,242, filed Dec. 28, 2001, entitled “SYSTEMAND METHOD FOR THE SYNCHRONIZATION OF A FILE IN A CACHE,” issued as U.S.Pat. No. 7,062,515 on Jun. 13, 2006. All applications listed in thisparagraph are hereby fully incorporated by reference herein.

TECHNICAL FIELD OF THE INVENTION

This invention relates generally to cache management and moreparticularly to a system and method of synchronizing a cached file witha database.

BACKGROUND OF THE INVENTION

Centralized databases are becoming increasingly popular for storingelectronic files or “database assets.” Most databases are operated undera client/server computer network model. In a client/server network, aclient computer requests information (e.g., makes a request for files ordatabase assets, etc.) from a server computer. In response to therequest, the server computer searches the database for the requestedinformation, retrieves the information, and communicates the informationto the requesting client computer.

Having a general repository of information such as a database isadvantageous because it allows multiple users to access the same filefrom various client computers, thereby allowing, for example, employeesfrom disparate departments to work together on the same project, thuspromoting efficiency and teamwork. Furthermore, because employees canaccess the database from remote computers via a network (e.g., LAN,Internet, etc.), the employee can access and work on files from home orwhile “on the road.” Thus, databases help support employee mobility andeven the most mobile employees can work with database assets so long asthe employee can establish a network connection to a database server(e.g., the computer responsible for handling database requests).

Additionally, databases free organizations from relying on individualusers to store files on local machines. Using a centralized database tostore files can decrease the likelihood that a file will be lost orcorrupted if an employee misplaces or damages his/her computer. Yetanother advantage provided by centralized databases is that anorganization can control user access to particular database assets.Through authentication and authorization (validation) processes, such asrequiring user names and/or passwords, an organization can govern whichemployees can work with particular files. This can help in controllingof work product and in ensuring quality control.

Because database assets are typically transported over a relatively slownetwork connection, a cache at a user's computer can be used to increasethe speed with which files can be accessed and modified modified. Acache typically stores a local copy of a database asset on the user'scomputer. Thus a user can access and modify a local copy of a file,which is generally much faster than accessing a file directly over anetwork. When a user makes a change to the local or “cached” file copy,the change can, as will be described below, be synchronized with thedatabase from which the file was originally retrieved.

Despite the many advantages provided by databases, databases alsopresent many challenges to organizations. Typically, an organization'sdatabase(s) include a myriad of different database asset types. Forexample, a corporation's database might include Microsoft™ Word™ files,Microsoft™ Excel™ files, WordPerfect™ files, text files, graphics files(e.g., .jpg, .tif, or .gif), html files, AutoCAD™ files, etc. Inaddition to storing multiple types of database assets, there may also bea number of different users trying to access the same files.

Adding to the complexity of database management, various users ofdatabase assets may prefer to use different tools (e.g., they will havea “tool of choice)” to modify different types of database assets. Thus,for example, one user may prefer to use Microsoft™ Word™ to edit wordprocessing documents while another user may prefer a different texteditor. Therefore, in managing a network incorporating a database, anorganization must be able to reconcile the multifarious subjective userpreferences.

Several systems have been developed in an attempt to meet the challengespresented by database management. One current system requires that usersemploy custom-designed tools in order to edit the assets in a database.While the custom-designed tools typically reduce latency byautomatically saving changes or modifications to the database, thesesystems are unattractive because they do not allow a user to seamlesslyemploy his/her tool of choice. Instead, the user must utilize a toolprovided by the database vendor or an external editor that is typicallycumbersome to use. Because he/she may not be familiar or efficient withthe tool, the user may require extra training and, consequently, thiscan result in extra expense to the employer or other organization.

A second option that is currently available allows a user to utilizestandard software tools (e.g., Microsoft™ Word™) to access and modifydatabase assets, but requires a second program (a “synchronizationprogram”) on the client machine to synchronize any modifications that auser makes on his/her client machine with the database. These systemsalso have several shortcomings. Primarily, synchronization programs aretypically designed to run with only one software tool (e.g., they act asa plug-in to an existing software application) or, if designed to runwith multiple programs, they require significant amounts of additionalcoding. Thus, a user will be able to use only the tools for which theorganization has a synchronization program in place. Therefore, a user'schoice in software is severely limited by the presence or absence of asynchronization program. Furthermore, these prior art systems typicallyrequire that the user take extra steps in saving data to the database.When a user saves a file on his/her local (e.g., client) machine, he/shetypically must also save the file in the synchronization program inorder to have the file saved to the database. While it may only take anadditional few seconds to save a file to the database using thesynchronization program (though it can take significantly longer,particularly to save large files to a remote database), over the courseof many saves this can lead to significant losses in time andproductivity. These systems are also deficient because they can lead tosignificant latency problems. If a user forgets to perform the extrastep of saving a file to the database using the synchronization program,any modifications that the user saved using a local program or tool willonly be saved locally and will not be reflected on the database untilthe user synchronizes the local file with the database. Thus, if a userforgets to save a file to the database using the synchronizationprogram, the database will not contain the latest version of a file fora potentially long period of time. Consequently, if another user accessthe file from the database before synchronization occurs, he or she willnot receive up-to-date information.

Yet another existing system for accessing and modifying database assetsthat has been developed is an operating system-level implementation thatcreates a file system on a local machine (e.g., a user's computer orclient computer), that allows the user to view database assets as if theassets were locally situated. In this system, the user sees the databasereflected as an additional virtual local storage device (e.g., an “E”drive). Database assets are depicted as files on the file system. When auser selects the database asset that he/she wants to edit (e.g., bydouble clicking on the asset), the database asset can be retrieved fromthe database and can be opened locally with whichever program isassociated with that particular type of asset (e.g., Adobe® PhotoShopcould open .jpg files). This system presents shortcomings, however,because it requires additional programming at the operating system“driver” level. Any defect or error in the program while the program isrunning can cause the local user's machine to cease functioning or“crash” until the operating system is reinitialized (e.g., until theclient computer is rebooted), significantly reducing user productivity,and leading to loss of data.

SUMMARY OF THE INVENTION

The invention provides a system and method of synchronizing a cache thatsubstantially eliminates or reduces disadvantages associated withpreviously developed systems and methods of synchronizing caches. Moreparticularly, embodiments of the invention provide a system and methodfor bi-directional synchronization of a cache. An embodiment of thesystem of this invention includes a software program stored on acomputer readable medium. The software programming can be executable bya computer processor to run in user space and perform steps comprising:receiving a database asset from a database; storing the database assetas a cached file in a cache; determining if the cached file has beenmodified; and, if the cached file has been modified, communicating thecached file to the database. In one embodiment of the invention, thesoftware program can determine if the cached file has been modifiedthrough automatic notification from a file management system.Alternatively, the software program can poll a cached file to determineif the cached file has changed. In another embodiment of the invention,the software program can be further executable to perform the step ofprompting an operating system to open the cached file in an applicationassociated with the cached file's file type. In another embodiment ofthe invention, the software program can be further executable to receivenotifications from a database of when contention for a database assetoccurs. Thus, bi-directional synchronization can occur.

Embodiments of the invention provide a technical advantage because theydo not require a user to manually save changes in a separatesynchronization program, thereby saving substantial time and reducinglatency.

Another technical advantage of the embodiments of the method and systemof the invention is the ability to synchronize cached filescorresponding to a multitude of file types. Because various embodimentsof the invention can synchronize cached files, regardless of the filetype, a user can employ his or her preferred tools of choice and he orshe will not have to rely on unfamiliar, custom designed applications.

Yet another technical advantage of embodiments of the invention is thecapability to seamlessly synchronize a cache with a database. Becauseembodiments of the invention can automatically determine if a cachedfile has been modified and can communicate the cached file to thedatabase, latency is substantially reduced.

Embodiments of the invention provide yet another technical advantage bybeing compatible with a variety of database and network architectures.

Still another technical advantage provided by embodiments of theinvention is the ability to reestablish database connections, thusincreasing the likelihood that synchronization will occur.

Embodiments of the invention provide yet another technical advantage byhaving the capability to receive notifications from the database whencontention for a database asset occurs. Because a user can be made awareof when another user attempts to access the same database asset, issuesof contention can be resolved more efficiently.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the invention and the advantagesthereof may be acquired by referring to the following description, takenin conjunction with the accompanying drawings in which like referencenumbers indicate like features and wherein:

FIG. 1 illustrates a network that can include a client computerutilizing a cache manager according to an embodiment the invention; and

FIG. 2 is a flow chart diagramming the operation of one embodiment ofthe method and system for synchronization of a cache according to theinvention.

DETAILED DESCRIPTION OF THE INVENTION

Preferred embodiments of the invention are illustrated in the figures,like numerals being used to refer to like and corresponding parts of thevarious drawings.

The embodiments of the method and system of the invention provide thecapability to seamlessly and transparently access database files locallyand synchronize cached files with a database. Embodiments of theinvention provide the ability to save a database asset as a local cachedfile, determine if the cached filed has been accessed or modified, andif the cached file has been accessed or modified, synchronize the cachedfile and the associated database (e.g., the database from which thedatabase asset was received). Additionally, the embodiments of theinvention can also provide the ability to open, view, and/or modifydatabase assets via a user's preferred application or software tool.

FIG. 1 illustrates a system 20 that can include a client computer 22utilizing a cache manager 38 for managing a cache 40 according to oneembodiment of the invention. System 20 can include at least one clientcomputer 22 and at least one server computer 24 (“Server 24”). Clientcomputer 22 can connect to server 24 via a network 26. Network 26 cancomprise any global computer network (e.g., the Internet), a wirelessnetwork, a local area network, or any other network capable oftransporting data between a client computer and a server. Clientcomputer 22 can be a personal computer, a workstation, a wirelessdevice, a laptop computer, or any other computer device operable toaccess data from a database. Client computer 22 can include a centralprocessing unit (CPU) 30 connected to a computer-readable memory 32.Memory 32 can comprise any combination of RAM, ROM, magnetic storagedevice, such as a hard drive, and/or other computer readable memoryknown in the art. Furthermore, while in FIG. 1 memory 32 is shown to beconnected locally to CPU 30 at client computer 22, memory 32 can bedistributed between several devices.

Memory 32 can store a number of computer programs, including anoperating system 34, various applications 36 (that can comprise softwaretools) that can include word processing tools or other software toolsknown to those in the art, and a cache manager 38 residing inuser-space. The concept of user-space is well-known to those of ordinaryskill in the art. Operating system 34 can further include a filemanagement system 35 to organize and keep track of files in memory 32.Memory 32 can also include a cache 40 which can contain cached versionsof database assets, such as cached file 42. As will be discussed ingreater detail below, cached file 42 can be a cached version, eithermodified or unmodified, of database asset 43. Client computer 22 canestablish network communication through a network connection device 44.Network connection device 44 can be any network communication devicethat is known to those in the art.

Server 24 can include standard server computer components, including aserver network connection device 46, a CPU 48, and a memory (primaryand/or secondary) 50. Network connection device 46, CPU 48, and memory50 can be equivalent components to network connection device 44, CPU 30,and memory 32 of client computer 22. Memory 50 can store databasemanagement program 52, which can be executable to carry out standarddatabase functions, including receiving requests for data, retrievingthe data, and returning the data to the requesting computer. Memory 50can also include a database 54, which can include various databaseassets, such as database asset 43. The database assets can include avariety of different file types, including, but not limited to, textfiles, spreadsheet files, graphics files, html files, etc.

It should be noted that the system architecture illustrated in FIG. 1 isby way of explanation only and is designed to give context to theembodiments of the invention. However, various embodiments of cachemanager 38 can be implemented with different architectures of clientcomputer 22 and/or server computer 24.

In operation, a user wishing to access database assets (e.g., databaseasset 43) can establish a connection through a standard networkapplication, as is known to those in the art, with a server (e.g.,server 24) associated with the database (e.g., database 54) on which theparticular database asset (e.g., database asset 43) is stored. Cachemanager 38 can be executable by CPU 30 to establish a connection withserver 24 in any manner known in the art of establishing databaseconnections through network connection device 44. As is understood bythose with ordinary skill in the art, access to a database typicallyrequires authentication with the database. Therefore, the user, wheninitially attempting to access server 24 (and database 54 associatedtherewith) may be required to enter login and authenticationinformation. As will be discussed in greater detail below, in oneembodiment of the invention, cache manager 38 can store the login andauthentication information so that if the connection to server 24 issubsequently dropped or lost, cache manager 38 can re-establish theconnection without requiring the user to re-enter his/her login and/orauthentication information.

Once the user has established a connection to server 24, cache manager38 can determine the contents of database 54 and can enumerate thecontents for display by a program in, for example, a graphical userinterface. In one embodiment of the invention, cache manager 38 caninterface with file management system 35 for display of the databaseassets in a pre-existing interface. In a hierarchical file managementsystem 35, for example, file management system 35 will use directoriesto organize files into a tree structure. Thus, in the case of ahierarchical file management system 35, cache manager 38 can interfacewith the hierarchical file management system 35 of operating system 34to display database 54 as an additional tree node in the directorydisplay and to organize database assets into the tree structure underthe database directory. In the well-known Microsoft™ Windows operatingsystem, database 54 could appear as an additional drive in a directorytree of the Windows Explorer display, and each database asset couldappear as a file under the database directory. Alternatively, ratherthan interfacing with file management system 35, cache manager 38 canprovide an independent and/or custom graphical user interface fororganizing representations of database assets.

The user can select a database asset in which he/she is interested fromthe graphical user interface used by cache manager 38 (e.g., either theindependent graphical user interface or the graphical user interfaceintegrated with file management system 35). When the user selects adatabase asset (e.g., database asset 43) by, for example, doubleclicking on the database asset in the Windows™ Explorer display, cachemanager 38 can determine if the connection to server 24 is stillestablished. If the connection has been lost, cache manager 38 canestablish a connection to server 24. If the connection is stillestablished, (or once the connection is re-established), cache manager38 can request the selected database asset (e.g., database asset 43).Database management program 52 will receive the request and searchdatabase 54 for database asset 43, retrieve database asset 43, andcommunicate a copy of database asset 43 to client computer 22 whiletypically maintaining a copy of database asset 43 on database 54. Cachemanager 38 can receive database asset 43 and store database asset 43 ascached file 42 on memory 32. In addition, cache manager 38 can associatecached file 42 with a particular connection (e.g., with a particulardatabase) so that if the user is accessing multiple databases, cachemanager 38 can keep track of the database from which a cached file wasretrieved. Cache manager 38 can also associate cached file 42 with aunique location on memory 32. In other words, cache manager 38 can storecached file 42 in a unique location in the file system of filemanagement system 35.

Assume, for example, that database asset 43 is the file “myfile.jpg”.When the user requests myfile.jpg, cache manager 38 can request the filefrom server 24. Database management program 52 can search database 54for myfile.jpg, retrieve myfile.jpg, and send a copy of myfile.jpg toclient computer 22 while retaining a copy on database 54. Cache manager38 can receive myfile.jpg and associate myfile.jpg with database 54.Cache manager 38 can also save myfile.jpg as cached file 42 in cache 40of memory 32 and associate myfile.jpg with a unique location in memory32. As an example, cache manager 38 could store myfile.jpg on a harddisk drive (e.g., in memory 32) as “C:\cache\db54\myfile.jpg.”

Operating system 34 can then open cached file 42 with whicheverapplication 36 is associated with the file type for cached file 42. Forexample, if cached file 42 was myfile.jpg and operating system 34normally opened .jpg files with Adobe™ Photoshop (“PhotoShop”) (e.g.,assume PhotoShop was associated with the .jpg file format), operatingsystem 34 would open myfile.jpg with PhotoShop. The user is then free toview or modify myfile.jpg (e.g., cached file 42) in PhotoShop (e.g.,application 36). As files can be opened with the application or softwareprograms that are associated with the particular file type, a user canutilize his/her preferred tool of choice to work on a file just as if(s)he were working from a file directly from file management system 35,providing a significant advantage over prior art systems.

After viewing and/or modifying myfile.jpg, the user can again save thefile. When the user saves cached file 42 (e.g., when the user savesmyfile.jpg in PhotoShop), cached file 42 can be saved in cache 40 ofmemory 32 at the location previously associated with cached file 42 bycache manager 38. In other words, application 36 will save cached file42 back to the location from which application 36 opened cached file 42.In the case of myfile.jpg, this could entail saving myfile.jpg back to“C:\cache\db54\myfile.jpg.”

In one embodiment of the invention, cache manager 38 can interface withfile management system 35 of operating system 34 to receive notificationof when a particular file (e.g., cached file 42) has been saved by theuser. For example, when a user saves a change to myfile.jpg, filemanagement system 35 can notify cache manager 38 that cached file 42 hasbeen saved. Thus, if file management system 35 supports automaticnotification, cache manager 38 can exploit an inherent feature of filemanagement system 35 to determine when cached file 42 is saved. Itshould be noted, however, that while the file management system 35 ofthe Microsoft™ Windows operating system allows for notification of whena file has changed, not all operating systems do so. If file managementsystem 35 does not support automatic notification of when files aresaved, cache manager 38 can poll cached file 42 to determine if cachedfile 42 has been modified. One method of polling files is disclosed inU.S. patent application Ser. No. 10/034,712, entitled “Method and Systemfor Optimizing Resources for Cache Management”, filed on Dec. 18, 2001,to inventors David Thomas and Scott Wells (the “ManagementApplication”), which is hereby fully incorporated by reference.

Upon determining that cached file 42 has been saved, cache manager 38can determine with which connection (e.g., with which database) cachedfile 42 is associated. In the continuing example of myfile.jpg, sincemyfile.jpg was received from database 54, myfile.jpg is associated withdatabase 54, as described earlier. If the connection with which cachedfile 42 is associated has been dropped or lost, cache manager 38 can, inone embodiment of the invention, re-establish the connection. This canbe done by using the previously stored login and authenticationinformation or by prompting the user to re-enter the login and/orauthentication information. If the connection was not dropped or whenthe connection is re-established, cache manager 38 can communicate acopy of cached file 42 directly (e.g., without the use of anintermediate synchronization program) to server 24. Because cachemanager 38 can re-establish lost or dropped connections, the user canstill save files back to database 54 following a dropped connection.

If, after several attempts, cache manager 38 cannot re-establish theconnection, cache manager 38 can notify the user that the connection hasbeen lost and give the user the opportunity to backup cached file 42.Additionally cache manager 38 can delete cached file 42 so that cache 40does not contain cached files that cannot be synchronized with adatabase because the connection associated with cached file 42 has beendropped.

It should be noted that even after cache manager 38 has communicatedcached file 42 to server 24, a copy of cached file 42 can remain onmemory 32 of client computer 22 so that the user can continue to work oncached file 42. Whenever cache manager 38 determines that cached file 42has again been saved or closed in application 36, either throughnotification from file management system 35 or through polling, cachemanager 38 can again communicate cached file 42 to server 24. Databasemanagement software 52 can then save cached file 42 as database asset43, thus synchronizing database 54 with cached filed 42.

As can be understood from the foregoing discussion, the invention canprovide substantial advantages over previously developed systems formanaging database assets. Because cache manager 38 can run in thebackground, a user's access to and modification of database assets canoccur essentially transparently. Furthermore, because embodiments ofcache manager 38 can interface with file management system 35 to receivenotifications of when changes occur to cached file 42, cache manager 38can quickly communicate the saved changes or modifications to database54, thus reducing the latency between when cached file 42 is modifiedand when corresponding database asset 43 is updated. Also, because cachemanager 38 can determine when cached file 42 has been saved, the userdoes not have to save cached file 42 in a separate synchronizationprogram. Furthermore, as cache manager 38 can reside in user-space,cache manager 38 is much less likely to de-stabilize client computer 22,as would an operating system level program. Also, cache manager 38 canbe transparent to the tools or applications used to access modify cachedfiles.

FIG. 1 illustrates a system in which there is one client computer 22 andone server 24. However, it should be noted that there may be many clientcomputers 22 and many servers 24. Potentially, a single user couldaccess multiple databases and several users could access the samedatabase. Because many users may be attempting to access the samedatabase, contention for the same database asset can occur. For example,while a first user is working on database asset 43 (e.g., is modifyingcached file 42) on his/her client computer 22, a second user couldattempt to access database asset 43 from database 54. In one embodimentof the invention, cache manager 38 can receive notifications fromdatabase management program 52 of when additional users access databaseasset 43. Cache manager 38 can then present, in a graphical userinterface, various choices to the user as to how to resolve thecontention over database asset 43. For example, the first user could begiven, in a dialog box, the choice to retrieve the latest version ofdatabase asset 43 with any changes made by the second user.Alternatively, database management program 52 could implement automaticrules such as giving priority to the first user, etc.

In addition to receiving notifications from database management program52 regarding database assets upon which a user is currently working,cache manager 38 can receive notifications regarding database assetsupon which the user has previously worked (e.g., database assets forwhich there is a corresponding cached file 42 in cache 40). Thus, forexample, if a user has previously worked on database asset 43 and aversion of cached file 42 remains in cache 40, cache manager 38 canreceive notifications regarding database asset 43. If database asset 43were changed by another user, cache manager 38 can receive anotification from database management program 52 regarding the changeand present the notification to the user (e.g., in a graphical userinterface such as a dialog box). Thus, cache manager 38 can receiveinformation regarding various database assets (e.g., database asset 43)upon which a user has worked. It should be noted that databasemanagement programs 52 that provide such notifications are well known inthe art.

Cache manager 38 can also receive notifications from database managementsystem 52 that a database asset for which there is a correspondingcached file 42 in cache 40 has been deleted from database 54. In oneembodiment of the invention, upon receipt of such notification, cachemanager 38 can notify the user via a graphical user interface that thedatabase asset has been removed and can purge the corresponding cachedfile 42 from cache 40.

By having the capability to seamlessly save changes to a cached file toa database and receive notifications from the database managementprogram regarding the associated database asset, cache manager 38 canparticipate in bi-directional synchronization of the cache. That is,cache manager 38 can synchronize database asset 43 with cached file 42whenever changes are made (or detected via polling) to cached file 42,and cache manager 38 can notify a user of changes made by others todatabase asset 43. Thus, database asset 43 can reflect the most recentchanges made by a user to cached file 42 and users can be made aware ofchanges made by others to database asset 43.

FIG. 2 is a flow chart diagramming the operation of one embodiment ofthe method and system for cache synchronization of this invention. Atstep 60, cache manager 38 can receive a request to establish aconnection to database 54. The request can occur, for example, inresponse to an employee attempting to connect to a corporate database.Cache manager 38 can establish a connection to a server associated withdatabase 54 (e.g., server 24), at step 62, via standard networkcommunication device 44. As would be understood by those of ordinaryskill in the art, access to a database often requires that a user entera login and/or other authentication information. To prevent the userfrom having to re-enter this information if the connection to server 24is dropped or lost, cache manager 38, at step 63, can save the login orauthentication information. Cache manager 38, at step 64, can providethe contents of the database (e.g., database 54) to an externalgraphical user interface. In one embodiment of the invention, thegraphical user interface can be integrated into an interface provided byfile management system 35 of operating system 34. Thus, in a Microsoft®Windows environment, database 54 could appear as an additional tree nodein a directory display in the Windows Explorer file management systemand each database asset associated with database 54 can appear as a filein the file tree display of the Windows® Explorer display. In analternative embodiment of the invention, cache manager 38, at step 64,can display the database contents in an independent graphical userinterface. This can be done in systems where integration with operatingsystem 34 and its associated file management system 35 cannot be easilyachieved.

Based on the database assets displayed in the graphical user interface,the user can select the database asset with which he/she wishes to work(e.g., database asset 43). This can be done in a Windows-basedenvironment, for example, by the user double clicking on the databaseasset displayed in the Windows Explorer display. At step 68, cachemanager 38 can receive a request for the selected database asset. Cachemanager 38 can then determine, at step 70, if the connection to thedatabase with which the database asset is associated (e.g., database 54)is still present or whether it has been dropped or disconnected. If theconnection has been dropped or disconnected, cache manager 38, at step71, can re-establish the connection using either re-entered login and/orauthentication information from the user or login and/or authenticationinformation that was saved at step 63. After the connection isre-established, or if the connection was not dropped or disconnected asdetermined at step 70, cache manager 38, at step 72, can make a requestto server 24 for the selected database asset.

At server 24, database management program 52 can receive the request forthe selected database asset (e.g., database asset 43), search database54 for the database asset, and, if the database asset is found,communicate the database asset to client computer 22. At step 76, cachemanager 38 can receive a copy of the database asset and save the copy ofthe database asset as cached file 42 in cache 40 of memory 32.Additionally, at step 78, cache manager 38 can associate the cached file42 with a particular connection. Because cached files are associatedwith a particular connection, cache manager 38 will be able tocommunicate changes associated with a database asset (e.g., changes tothe corresponding cache file) back to the appropriate (e.g., theassociated) database. Cache manager 38, at step 80, can also associatecached file 42 with a unique location in memory 32 (e.g., at cache 40 ofclient computer 22). Thus, for example, if database asset 43 was thefile myfile.jpg, cache manager 38 can save database asset 43 as cachedfile 42 at the location “C: \cache\db54\myfile.jpg.”

Cache manager 38, at step 82, can prompt operating system 34 to opencached file 42 (e.g., myfile.jpg). Operating system 34 can open cachedfile 42 with the application 36 with which operating system 34 (or theuser) would normally open such a file. Thus, for example, if .jpg fileswere associated with PhotoShop, operating system 34 can open myfile.jpgwith PhotoShop (e.g., application 36) from “C:\cache\db54\myfile.jpg.”The user can then view and/or modify cached file 42 (e.g., myfile.jpg)in the appropriate application 36 (e.g., PhotoShop).

In order to synchronize database asset 43 with cached file 42, cachemanager 38, at step 84, can determine if the cached file 42 has beenmodified. As described earlier, this can be done either throughreceiving notification from file management system 35 that cached file42 has been saved or by polling cached file 42 to determine if the filehas changed. As described in the Management Application, polling can bedone, for example, by reading a time stamp associated with cached file42 to determine the last time at which cached file 42 was modified. Ifthe time stamp from the most recent polling of cached file 42 does notmatch the time stamp from a previous polling of cached file 42, thencached file 42 has been modified and cache manager 38 can attempt tosynchronize cached file 42 with database 54. As can be understood bythose of ordinary skill in the art, the frequency at which cache manager38 polls cached file 42 can be adjusted to optimize the resources ofclient computer 22. A more frequent polling will require more resourcesbut will result in a lower latency between the time when a cached file42 is modified and when cache manager 38 determines cached file 42 hasbeen modified. Conversely, a longer time interval between each pollingof cached file 42 will reduce the required resources of client computer22 but can lead to a longer latency period. Thus, the polling intervalcan be set to optimize system resources with respect to latency period.

Returning now to FIG. 2, if at step 84 cache manager 38 determines thatcached file 42 has not been modified (e.g., changed, deleted, etc.),cache manager 38 can continue to either poll cached file 42 formodifications or wait for file management system 35 to indicate thatcached file 42 has been modified. If, on the other hand, cache manager38 determines at step 84 that cached file 42 has been modified (e.g.,through polling or notification from file management system 35), cachemanager 38 can determine, at step 86, if the connection associated withcached file 42 (e.g., the connection to database 54 over which cachemanager 38 received database asset 43) is still established. If theconnection has been dropped, cache manager 38 can re-establish theconnection at step 88. If login or authentication information isrequired to re-establish the connection, cache manager 38 can use thelogin or authentication information saved from the user at step 63 or,alternatively, prompt the user to enter new login and/or authenticationinformation. Once the connection has been re-established at step 88 (or,if at step 86 cache manager 38 determined that the connection associatedwith cached file 42 was still established), cache manager 38, at step90, can save a copy of cached file 42 directly to database 54 (e.g.,without the need for an intermediate synchronization program). Cachedfile 42 can then be saved as database asset 43, and thus, database 54can be synchronized with the most recent changes made to cached file 42.At step 92, cache manager 38 can optionally repeat steps 84-90 forcached file 42 until the user ceases work on cached file 42 or,alternatively, cached file 42 expires (some pre-determined amount oftime passes during which cached file 42 is not viewed or modified).

Because cached file 42 can be communicated to database 54 immediately oralmost immediately after cached file 42 has been modified, databaseasset 43 can more accurately reflect the latest revisions to databaseasset 43. Thus, subsequent users accessing database asset 43 are ensuredof having the latest revisions to database asset 43. Furthermore,because cache manager 38 can use inherent notification features of filemanagement system 35 or can automatically poll cached file 42 forchanges, the invention does not require the user to save cached file 42to database 54 using a separate synchronization program, thereby furtherreducing latency. Additionally, by omitting the extra step of savingcached file 42 in a synchronization program, the user can save time eachtime he/she modifies a cached file.

The teachings of the invention provide an additional advantage byenabling the “seamless” use of tools of choice. Because cache manager 38can prompt operating system 34 to open cached file 42 in the application36 with which the file type of cached file 42 is normally associated,users can use their tools of choice to modify and view database assetswithout having to rely on custom designed and unfamiliar tools providedby database vendors or on being limited to using only those tools forwhich a synchronization program exists. Additionally, because cachemanager 38 resides at the file system level rather than at the operatingsystem level (e.g., resides in user space, rather than operating space),cache manager 38 is less likely to degrade the stability of clientcomputer 22.

In addition to reducing latency, empowering tools of choice, andmaintaining stability of client computer 22, cache manager 38 can helpresolve contention between various users for the same database asset. Ascan be understood by those of ordinary skill in the art, embodiments ofdatabase management software program 52 can send notification of when auser attempts to access a database asset. For example, databasemanagement software program 52 could send a notification to cachemanager 38 when an additional user attempts to access a database asset43. Cache manager 38 can then send a notification to the first user, viaa graphical user interface, that another user is attempting to accessdatabase asset 43. In one embodiment of the invention, this can occurwhether or not the first user is currently working on cached file 42.The first user can be given various options, such as to view the latestversion of database asset 43 or, if the first user is currentlymodifying cached file 42, overriding changes made by any other user todatabase asset 43.

Because cache manager 38 can be notified when other users attempt tomodify database asset 43, each user who has previously accessed andmodified database asset 43 can be made aware of changes to that databaseasset. Thus, if several members of a team are working on a projectinvolving database asset 43, each member can be made aware of whenanother member of the team (or some other user) modifies or accessesdatabase asset 43, thereby aiding in control of the database asset.Furthermore, cache manager 38 can provide bi-directional synchronizationof database asset 43 by not only saving changes made to cached file 42to database 54, but also by notifying users of changes in database asset43.

As can be understood from the foregoing discussion, embodiments of theinvention provide a system for seamlessly and transparentlysynchronizing database assets as users work on those assets. Embodimentsof the invention also provide the advantage of allowing users to employtools of choice without having to perform the extra steps required forsaving a database asset through a separate synchronization program.Additionally, the teachings of the invention enable the use of tools ofchoice regardless of a database asset's file type. Further, embodimentsof the invention are less likely to degrade the stability of clientcomputer 22.

Although the invention has been described in detail herein withreference to the illustrative embodiments, it should be understood thatthe description is by way of example only and is not to be construed ina limiting sense. It is to be further understood, therefore, thatnumerous changes in the details of the embodiments of this invention andadditional embodiments of this invention will be apparent to, and may bemade by, persons of ordinary skill in the art having reference to thisdescription. It is contemplated that all such changes and additionalembodiments are within the spirit and true scope of this invention asclaimed below.

What is claimed is:
 1. A computer system comprising: a client computerprocessor; a client computer network connection device coupled to theprocessor and operable to connect to a network; a client computer memorycoupled to the client computer processor the client memory havingoperating system space and user space; a client computer operatingsystem having an operating system file management system; a user spacecache manager in the client computer memory, the user space cachemanager executable by the processor to perform operations comprising:communicating with a server over the network to download a copy of afile from a file repository; storing the downloaded file as a cachedfile in a local cache at the client computer, wherein the local cachecomprises a location in a file system of the file management system;interfacing with the file management system of the client computeroperating system such that the client computer operating system providesthe cache manager automatic notifications of changes in the local cache;in response to receiving an automatic notification, determining if thecached file has been modified by another application; and when it hasbeen determined that the cached file has been modified, sending changesto the cached file to the server to synchronize the file at the filerepository with the cached file.